1. Technical Field
The present invention relates generally to an intervertebral cage for spinal implants and, more particularly, to an intervertebral cage for spinal implants configured such that the cage can be mounted freely in front, lateral side or inclined direction relative to the vertebrae, wherein the front side has a trapezium face, the right lateral side and left lateral side are configured such that a left vertical line and a right vertical line are lengthened, and the length of the right vertical line of the left lateral is a shorter than that of the left vertical line of the right lateral, and the front side and the right lateral include a plurality of holes to which a tool is temporarily coupled.
2. Description of the Related Art
In general, an intervertebral cage for spinal implants is inserted into a disc-removed intervertebral gap and is an artificial prostheses apparatus for restoring and maintaining an interval between two vertebrae. Such an intervertebral cage for the spinal implants is currently formed in various shapes and is widely used to surge the vertebrae.
However, in order to replace a spinal disc due to abrasion of the disc, a frontal and lateral cage that is inserted at the position of the worn spinal disc has been currently developed and is used for the spinal disc operation.
FIGS. 1 to 3 are a perspective view, a plan view and a side view showing a conventional intervertebral cage, respectively.
As shown in FIGS. 1 to 3, a conventional intervertebral cage 10 has a width (horizontal length in the figures) and a height corresponding to the width and height of a disc (36 in FIG. 4) positioned between vertebral bodies (32 and 34 in FIG. 4 and 34 in FIG. 5); a through hole 14 having a width vertically elongated is provided at the center of the intervertebral cage; small circular holes 17 and 18 are formed at the central portion of the front and back of the cage, respectively, so that these holes communicate with the through hole 14; a plurality of teeth 15, 16 and 19 are formed in an upper and bottom sides of the cage that are contacted with and adjacent to a lateral part of the through hole 14; and a groove 13 is formed at both laterals of a right lateral 11 of the cage.
The method of using the above-mentioned conventional lateral cage 10 will be described as follows:
Before the lateral cage 10 is inserted into a damaged disc of a patient whose a spinal disc is worn or damaged, granulated bone chips are mixed with the patient's bone marrow or blood and then inserted into the through hole 14 of the lateral cage 10 and hardened. Next, as shown in FIG. 4, the groove 13 formed at both sides of the right lateral 11 of the lateral cage 10 is picked up with pincers (20 in FIG. 4) and the lateral cage is inserted into the position of the damaged disc 36 between the bodies 32 and 34 of the spine through an incised lateral side corresponding to the damaged disc of patients. At this time, the lateral cage may be inserted by knocking on the pincers using a kind of hammer.
FIG. 5 is a plan view showing the inserted lateral cage. The conventional lateral cage has a problem as follows:
First of all, a frontal cage may be used only in a frontal direction and a lateral cage may be used only in a lateral direction. The lateral cage cannot be replaced with the frontal cage during actual surgery, and if the frontal cage instead of the lateral cage is inserted by force in the case wherein there is a narrow space between the discs, it may cause damage to a vertebral disc. This results in complications such as non-union of the spine during use.
Also, since the height of the tip of a left lateral 12 of the lateral cage 10 that is first inserted into patient's spine during surgery, is formed to be substantially the same as that of the other part, a great amount of power must be applied between the vertebrae in the case wherein there is a narrow space between the discs and this may cause the vertebra board to be damaged. Further, if a great amount of power is applied, a bone chip 40 (FIG. 5) may be lost before it is placed between the vertebrae and so complications such as non-union of the spine may be caused while the vertebral surgery time is elapsed.
Also, FIGS. 6 and 7 show an intervertebral cage of the prior art (Japanese un-examined Laid-open publication No. 9-503416; Japanese patent application No. 199-511847). An intervertebral cage 50 comprises a pair of left and right semicircular lateral spacers 51A and 51B, a front and a rear central spacers 53A and 53B integrally fixed to each other by left and right fixing screws 55. The intervertebral cage 50 is inserted between an upper intervertebral body 59U and a lower intervertebral body 59L after removal of a disc. A cavity 57 is formed by the central spacers 53A and 53B and the lateral spacers 51A and 51B.
The intervertebral cage 50 of the prior art has problems in that 1) the cage consists of a large number of components and has a complex structure and 2) the cage cannot secure enough between the vertebrae after the insertion between the vertebral bodies, because they do not have a projection for preventing a loss of the intervertebral cage. Further, the intervertebral cage 50 of the prior art is inserted between the upper body and the lower body from a frontal direction, but it is not inserted from the vertical direction to an inclined front side. Accordingly, an improved intervertebral cage is required. That is, the intervertebral cage of the prior art has separate configurations for cases in which there is a front cage, a lateral cage, or an inclined cage, etc. and other configurations of the auxiliary apparatuses are also used as the other components.